Short CommunicationIntestinal stem cell ablation reveals differential requirements for survival in response to chemical challenge

- Headcase (Hdc) is a marker of intestinal stem cells (ISCs) and enteroblasts (EBs).
- Depletion of Hdc leads to loss of ISCs and EBs.
- Ablation of ISCs does not compromise lifespan under homeostatic conditions.
- ISCs are necessary for intestinal regeneration and survival in response to damage.

The Drosophila intestine is maintained by multipotent intestinal stem cells (ISCs). Although increased intestinal stem cell (ISC) proliferation has been correlated with a decrease in longevity, there is some discrepancy regarding whether a decrease or block in proliferation also has negative consequences. Here we identify headcase (hdc) as a novel marker of ISCs and enteroblasts (EBs) and demonstrate that Hdc function is required to prevent ISC/EB loss through apoptosis. Hdc depletion was used as a strategy to ablate ISCs and EBs in order to test the ability of flies to survive without ISC function. While flies lacking ISCs showed no major decrease in survival under unchallenged conditions, flies depleted of ISCs and EBs exhibited decreased survival rates in response to damage to mature enterocytes (EC) that line the intestinal lumen. Our findings indicate that constant renewal of the intestinal epithelium is not absolutely necessary under normal laboratory conditions, but it is important in the context of widespread chemical-induced damage when significant repair is necessary.